The monetisation of aircraft noise effects
A new study, written by two noise specialists from Berry Environment Ltd. and Anderson Acoustics, has reviewed the latest evidence and current policy in the UK on how noise impacts on health and wellbeing are given a monetary value for cost-benefit analysis.
The Airports Commission’s approach
The paper concludes that the Airports Commission’s approach to monetising noise has limitations, particularly in relation to noise annoyance. According to the research, the Commission’s approach would not accurately reflect annoyance from aircraft noise as the “dose-response” relationship it is based on is derived from non-aviation noise sources and people react differently to aircraft noise. In addition, the approach is based purely on changes to house prices, and therefore fails to take full account of the complexity of people’s preferences, the authors argue.
While the Commission’s methodology does allow comparison between short-listed runway options, the report argues its findings would be unlikely to accurately describe the actual health and annoyance impacts of a new runway.
Latest evidence on the monetisation of noise impacts
The two authors in this report highlight that while the evidence in relation to the physical health impacts from aircraft noise is well established, there is less evidence on the noise thresholds above which health and well being impacts occur. This, the report argues, makes it harder to give a monetary value to noise impacts.
The study contains a table with indicators for the strength of evidence supporting a relationship between noise and specific impacts.
In almost all cases, including annoyance, sleep deprivation, cardiovascular impacts, and cognitive development, there is sufficient evidence to support an association between noise and the impacts. However, as aircraft noise is only a single factor, the table suggests that evidence of specific ‘dose-response’ relationships is weaker.
Can noise be appropriately monetised?
The study recommends that to assess whether or not the impact of aircraft noise on a given health impact can be effectively monetised there must be:
- sufficiently strong evidence of the link between the health outcome and noise exposure;
- a robust “dose-response” relationship between the health impact on noise exposure, i.e. understanding of how much the risk of that health impact increases with given levels of noise;
- an appropriate monetisation policy for the level of noise;
- awareness of the possible limitations of the approach used to apply an economic value to the noise impacts, whether in terms of health or wellbeing.
The need for monetising noise impacts
We agree with the report’s finding that the impacts that aircraft noise has on people and health are wide ranging and complex, and that they vary depending on social, personal and attitudinal factors (see below image). This means that the noise impacts of airport expansion or a change in flight path are often overlooked as being too complicated to monetise or too subjective.
We also agree that there is “no silver bullet” for monetising the effects of aircraft noise. However, applying a monetary value to the impacts of aircraft noise on both health and wellbeing provides a way to include noise impacts in policy decision-making which are often primarily based on economic considerations. We therefore welcome the progress that has been made in this area of research.
However, we are a long way from being able to fully account for the impacts of noise with monetary values, and if noise impacts were considered by the Airports Commission only in terms of their estimates noise and health costs using the methods proposed, it is likely that communities would feel their concerns are not being entirely considered and that the monetary values given are not truly reflective of how they experience aircraft noise.
Alternative approaches might generate very different noise costs. For example it would be possible to set a target to limit aviation noise to a given decibel level and then to calculate the cost of bringing noise down to this level – whether by limiting aircraft activity or by using quieter aircraft. Such an approach, which focuses on the cost of reducing the issue rather than the cost of the damage caused by the issue, is now widely used in relation to applying a monetary value to carbon dioxide emissions.